水平层状复合岩体变形破坏特征的围压效应研究

为研究不同围压下深部复合地层岩体变形和破坏特征，结合地质赋存条件制作了类层状复合岩石试样，通过开展不同围压下的三轴压缩试验，研究了围压对水平层状复合岩体变形破坏特征的影响。试验结果表明：随着围压的不断增加，峰后偏应力-应变曲线的降低速率逐渐变缓，应变软化程度逐渐减弱；随着围压的增大，水平层状复合岩石的破坏形态呈现出明显差异，整体上破坏形态逐渐由脆性破坏向延性破坏过渡；在一定围压状态下，围压对软岩膨胀变形的约束效果相对硬岩较弱，导致水平层状复合岩石试样的软、硬分层之间的膨胀变形不协调，在层间黏结力作用下，软、硬分层之间发生相对错动现象。该研究成果对于施工单位预防深部复合地层隧道掘进机（TBM）工程灾害具有一定的指导意义。

Effect of confining pressure on mechanical properties of horizontal layered composite rock

In order to investigate the effect of confining pressure on deformation and failure characteristics of deep mixed ground, many specimens were made to mimic layered composite rock, considering the geological formation characteristics. Triaxial compression tests were carried out on these specimens to study the effect of confining pressure on deformation and failure characteristics of horizontal layered composite rock. The results showed that: with the increasing of confining pressure, the decreasing rate of partial stress-strain curves became slower and the degree of strain softening was gradually weakened; the damage form of horizontal layered composite rocks evolved with the increase of confining pressure and was translated from brittle to ductile. Under certain confining pressure, the constraint effect of confining pressure on soft rock expansion deformation was weaker than hard rock, which led to uncoordinated expansion deformation between the soft and hard layers. The relative dislocation occurred between the soft and hard layers under the influence of interlayer adhesion. These results can guide construction units to prevent and control the disaster of tunnel boring machine (TBM) in tunneling through deep mixed ground.